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Pegoraro P.A.,University of Cagliari | Pegoraro P.A.,RandD Group | Sulis S.,University of Cagliari
IEEE Transactions on Instrumentation and Measurement | Year: 2013

Distribution systems require ad hoc estimators, distribution system state estimation (DSSE) techniques, to acquire knowledge about the system status. An incorrect evaluation of the accuracy of the DSSE creates decision risks in network management. The possible variations in the network parameter values and the decays of the metrological characteristics of the measurement system elements are uncertainty sources very often not considered. Considering these possible lacks of accuracy, this paper focuses on the robustness of distributed measurement systems aimed to obtain accurate DSSE results. The problem of the proper assessment of the accuracy of the DSSE results obtained through a weighted least squares (WLS) approach is faced. A method capable of including different uncertainty sources in the uncertainty estimation of the WLS approach is presented. Furthermore, this paper proposes an optimal meter placement algorithm robust with respect to possible malfunctions in measurement system components. The results obtained on a portion of an Italian distribution network, along with their accuracy, are presented and discussed. © 1963-2012 IEEE. Source

Ribeiro G.B.,RandD Group | Barbosa Jr. J.R.,Federal University of Santa Catarina
Applied Thermal Engineering | Year: 2013

Experimental work was conducted to compare the thermal-hydraulic performances of cross-flow microchannel condensers using louvered fins and metal foams as extended surfaces. Three copper foam surfaces with pore densities of 10 and 20 pores per inch (PPI) and porosities of 89.3 and 94.7%, and three aluminum louvered fins with lengths of 27 and 32 mm (in the flow direction) and heights of 5 and 7.5 mm were evaluated. The experiments were carried out in a closed loop wind-tunnel calorimeter equipped with a R-600a refrigeration loop. A condensing temperature of 45 °C was used in all tests, with face velocities ranging from 2.1 to 7.7 m/s. A comparison based on the thermal conductance and air-side pumping power showed that the surfaces enhanced with louvered fins performed better than the metal foams under all conditions investigated. © 2012 Elsevier Ltd. All rights reserved. Source

Sezer S.,Queens University of Belfast | Scott-Hayward S.,Queens University of Belfast | Chouhan P.,Queens University of Belfast | Fraser B.,RandD Group | And 5 more authors.
IEEE Communications Magazine | Year: 2013

Cloud services are exploding, and organizations are converging their data centers in order to take advantage of the predictability, continuity, and quality of service delivered by virtualization technologies. In parallel, energy-efficient and high-security networking is of increasing importance. Network operators, and service and product providers require a new network solution to efficiently tackle the increasing demands of this changing network landscape. Softwaredefined networking has emerged as an efficient network technology capable of supporting the dynamic nature of future network functions and intelligent applications while lowering operating costs through simplified hardware, software, and management. In this article, the question of how to achieve a successful carrier grade network with software-defined networking is raised. Specific focus is placed on the challenges of network performance, scalability, security, and interoperability with the proposal of potential solution directions. © 1979-2012 IEEE. Source

Zinder E.Z.,RandD Group | Yunatova I.G.,RandD Group
Communications in Computer and Information Science | Year: 2013

An approach to organizing knowledge acquisition and management (KAM) and an appropriate conceptual framework for wide competency management sphere and other traditional humanities subject domains (SD) are described. The main purpose of the approach is to support possibility of SD experts work not only with the knowledge, but also with the knowledge metamodel without knowledge engineers' participation. The framework combines methods of knowledge elicitation and description well-known in humanities with formal methods for knowledge modeling. The framework includes the set of principles, a model of multidimensional space for visualization of continuing education (LifeLong Learning Space, LLLS), normalized competency metamodel (NCMM), and the process of NCMM tailoring. LLLS is used as domain-specific KAM goals model and as a tool for intuitively obvious goals visualization. Well-order and partial order relationships defined on LLLS dimensions are used for competency profiles evaluation and comparison. NCMM facilitates KAM process structuring and control. Rules for KAM process support and performance are described. The types of completed projects for more specific domains are mentioned. © Springer-Verlag Berlin Heidelberg 2013. Source

Gavasane M.,RandD Group | Ali A.U.,RandD Group | Samagod A.,RandD Group | Kaundinya J.,RandD Group | And 9 more authors.
BioPharm International | Year: 2013

Demonstration of viral clearance is crucial for the recombinant proteins produced from mammalian cell culture. Size exclusion-based filtration is one of the methods for viral clearance valid for different types of mammalian viruses. In this study, the initial hydraulic performance of the virus filtration has enabled the development of a validation protocol and high-log reduction values (LRVs) for an appropriate panel of mammalian viruses (during spiking studies) with the desired throughput. This is essential to minimize the filter area, the cost of this unit operation, and to achieve a robust process. All of the four panel viruses (i.e., MuLV, PRV, Reo-3, and MVM) were evaluated during spiking studies. A high throughput of 1250 L/m 2 was obtained with a high flux because of low protein concentration. This was validated for a predefined throughput of 387 L/m 2 with high values of LRVs (>5) achieved resulting in the relatively small area of virus filter (0.04m 2) for a 50-L batch volume to be processed in 2 h. This study on a recombinant human follicle stimulating hormone (rhFSH) demonstrates the use of virus filters to reduce the risk of contamination and provide a robust process of virus filtration. © 2013 Advanstar Communications, Inc. Source

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